Indoor Air Pressure Management

ABSTRACT

A strategy for minimizing or avoiding the so-called stack effect within buildings ( 20 ) includes controlling the temperature within a vertically extending shaft ( 40 ) such as an elevator hoistway or stairwell. Controlling the air pressure at each of a plurality of levels (A, B, C, D) within the useable or occupied space of a building ( 20 ) allows for controlling a pressure differential between the useable or occupied space and an interior of the shaft ( 40 ). Maintaining appropriate pressure differential levels allows for minimizing or avoiding the stack effect that otherwise results in undesirably large drafts between the building interior and the outside, surrounding environment.

FIELD OF THE INVENTION

This invention generally relates to controlling air pressure withinbuildings. More particularly, this invention relates to controlling airpressure within a building to avoid pressure differentials that resultin undesirable airflow between the interior of the building and theoutside, surrounding environment.

DESCRIPTION OF THE RELATED ART

There are a variety of situations where airflow management and airpressure

management within a building is desirable and necessary. Variousbuilding configurations require controlling airflow between the buildinginterior and the space outside of the building, for example, to preventundesirably large airflows through passageways (i.e., doorways) thatprovide access to the building. In some circumstances, the differencesin temperature between the inside and outside of the building and thebuilding configuration results in a pressure differential between theinside of the building and the outside environment that results inundesirably large drafts or even gusts between the building interior andthe outside, surrounding environment. Such drafts undesirably alter theheat load of the building and may interfere with comfortable passagethrough a doorway, for example.

One example undesirable airflow through a passageway between a buildingand an outside area may occur in a high rise building that includes atall shaft such as an elevator hoistway or a stairwell. Such shaftsallow for the so-called stack effect when there are differences betweenthe indoor and outdoor temperatures. The stack effect results in largedrafts of air through passageways (i.e., doorways) that provide accessto the building when such passageways are open. The difference inpressure between the building interior and the outside environment andthe stack effect cause such airflow.

For example, colder air outside of a building during a winter season isheavier than the warm air inside the building. The outside pressure ishigher than the inside pressure at lower levels of the building. Atupper levels of high rise buildings, the outside pressure is lower thanthe inside pressure under many circumstances. Accordingly, when there isan opening (such as at a doorway at a lobby entry level of a building)air tends to infiltrate into the building at the lower levels. The airtends to flow toward the top of the building. As airflow tends toward apath of least resistance, the outside air entering the building tends torise through a vertical shaft such as an elevator hoistway or stairwelltoward the top of the building.

One example patent: showing a stack-effect-reducing arrangement is shownin the Japanese Patent Publication No. 07-330247, which was published inDecember, 1995. Thai document proposes adding cool air to an elevatorshaft using suction to draw in outdoor air. That arrangement haslimitations.

A typical approach to address undesirable airflow between a building andthe surrounding outside environment is to attempt to seal the buildingfrom the outside environment Sealing passageways between fee buildinginterior and the outside typically is accomplished using revolvingdoors. There are various shortcomings and drawbacks associated with thatapproach. For example, revolving doors tend to limit the number ofindividuals that can pass through a doorway at any given time. Toincrease the potential traffic flow, larger revolving doors with largermotors have been introduced. This approach is nu ideal because thelarger equipment introduces additional cost and requires additionalspace.

Another drawback associated with revolving doors is that individualsdesiring to pass through an automatically moveable door tend to becomeanxious about timing their entry into the passageway based upon themotion of the door. In many situations, an individual is not allowed tomove slowly or to stop once they enter the vicinity of the revolvingdoor or they may be bumped, by one of the moving door panels.

There is a need for an improved arrangement that minimizes theoccurrence of the stack effect to improve airflow management associatedwith the interior of a building. Additionally, it would be beneficial tobe able to eliminate the requirement for revolving doors at buildingentrances. This invention addresses those needs while avoiding theshortcomings and drawbacks discussed above,

SUMMARY OF THE INVENTION

An exemplary disclosed method of controlling airflow within & buildingincludes controlling airflow through a generally vertical shaft in thebuilding. By maintaining a temperature in the shaft to correspond to anoutdoor temperature outside of the building and controlling an airpressure at each level of the building based upon the temperature in theshaft, the disclosed method minimizes the so-called stack effect.

In one example, the air pressures of at least some of the levels of thebuilding are adjusted responsive to a difference between pressure in theshaft and pressure in an occupied building space that is outside of aselected range. One example includes controlling the air pressure ateach building level individually. Another example includes grouping setsof building levels into zones and controlling the pressure Within eachzone.

A disclosed building includes a plurality of levels. At least one shaft,such as a stairwell or an elevator hoistway, extends generallyvertically and provides access to at least some of the plurality oflevels within the building. A temperature control mechanism associatedwith the shaft controls the temperature within the shaft such that thetemperature in the shaft corresponds to an outdoor temperature outsideof the building.

In one example, the temperature control mechanism includes openings nearopposite ends of the shaft to allow airflow between the shaft and theoutside of the building.

In one example, a pressure control device controls air pressure on eachof the plurality of levels to which the shaft provides access to controla pressure differential between the shaft and an occupied space in thebuilding. By controlling the air pressure on such levels, the pressuredifferential between the shaft and the floor levels can be controlled ina manner that minimizes the so-called stack effect.

The various features and advantages of this invention will becomeapparent to those skilled In the art from the following detaileddescription. The drawings that accompany the detailed description can bebriefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an example building.

FIG. 2 schematically illustrates selected control components of anexample embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically shows a building 20 that includes a plurality offloors or levels A, B, C, D... YY and ZZ. The example building 20 is ahigh rise building.

At least one vertically extending shaft 40 provides access to at leastsome of the levels within the budding. In one example, the shaft 40 isan elevator hoistway. In another example, the shaft 40 is a stairwell,

In the illustrated example, a temperature control mechanism isassociated with the shaft 40. In this example, the temperature controlmechanism comprises openings 42 and 44 that allow for airflow betweenthe interior of the shaft 40 and the environment outside of the building20, in this example, the openings 42 and 44 are near opposite ends ofthe shaft to allow a flow passage through the shaft for the outside airto flow through the shaft. Allowing the outside air to flow through theshaft establishes a temperature within the shaft that corresponds to theoutside temperature. In some circumstances, the outside temperature anddie temperature within the shaft will be approximately equal.

FIG. 2 schematically illustrates selected control components of oneexample embodiment. In this example, a temperature sensor 50 issupported within the shaft 40 to provide an indication of a temperaturewithin at least a portion of the shaft 40. Depending on the length ofthe shaft, a plurality of temperature sensors may be spaced along theheight of die shaft, A plurality of temperature sensors also allows foraccommodating differences in temperature that may occur along the lengthof the shaft,

A controller 52 receives information from the temperature sensor 50regarding the temperature within the shaft 40. The controller 52 in oneexample also receives information regarding an outside temperatureoutside of the building 20, When the controller 52 determines that thereis a difference between the temperature in the shaft and the temperatureoutside of the building 20 and the difference is outside of a selectedrange, the controller 52 activates an air mover 54 to increase theamount of outside airflow into the shaft 40. In one example, the airmover 54 comprises a fan.

In one example, the direction of air movement within the shaft 40 Iscontrolled depending on the outside temperature. On relatively cold days(i.e., the outside temperature is lower than that inside the building)the air is directed through the shaft from the bottom toward the top.This is accomplished using one or more air movers 54 associated with oneor more of the openings 42, 44 or otherwise positioned to achieve suchairflow through the shaft 40. On relatively warm days (i.e., when theoutside temperature is higher than that inside the building) the air isdirected from the top toward the bottom of the shaft 40. This isaccomplished in one example using at least one air mover 54 to cause thedesired direction of airflow through the shaft.

Directing the air movement through the shaft depending on the outsidetemperature ensures that the outside air in the shaft travels as desiredand does not enter the useable or occupied space within the building.

By maintaining a correspondence between the temperature within the shaft40 and the temperature outside of the building 20, the pressuredifferential between the shaft and the outside of the building isminimized. This facilitates minimizing die so-called stack effect. Hiedisclosed example of FIG. 2 also includes an arrangement for managingpressure at the different levels within the building 20 to minimize apressure differential between the shaft 40 and the useable or occupiedspace on each level.

In one example, the temperatures in any stairwell are controlled tocorrespond to the temperature control in an elevator shaft. This examplecoordinates temperature management in ail shafts 40 within a building toavoid having pressure increases on stairwell doors, which mightotherwise occur if only elevator shaft temperatures were controlled.

Considering the example of FIG. 2, a controller 60 controls the airpressure on an example level YY of the building 20 for even furtherenhanced airflow control, in this example, the controller 60 controls anair mover 62, such as one associated with a known HVAC system, toincrease or decrease the amount of airflow onto the level YY to therebyincrease or decrease the air pressure on that level of the building. Inthe illustrated example, the controller 60 receives information from thetemperature sensor 50 regarding the temperature within the shaft 40 tomake appropriate air pressure adjustments on the building level. Thetemperature within the shaft 40 is related to the pressure within theshaft in a generally known .manner. The controller 60 uses suchinformation for maintaining an air pressure in the useable or occupiedspace of the building level YY to achieve the desired pressuredifferential between the building level and the shaft 40.

In the example of FIG. 2, a pressure sensor 64 is provided at anappropriate location within the useable or occupied space of thebuilding level YY so that the controller 60 may make appropriate airpressure adjustments to achieve the desired pressure differentialbetween the useable or occupied space and the shaft 40. In one example,some pressure difference will be accommodated. In another example, thecontroller 60 is programmed to maintain air pressure on the buildinglevel such thai there is effectively no pressure difference between theuseable or occupied space on that level and the corresponding portion ofthe shaft 40.

Controlling the air pressure at the building levels to control thepressure differential between the interior of the shaft 40 and theuseable or occupied space on each level allows for minimizing theoccurrence of the so-called stack effect because there is not a pressuredifferential that tends to instigate significant airflow into the spacewithin the shaft 40. This allows for not requiring the type of sealingat building entrances that is typically accomplished using revolvingdoors, for example. By effectively managing the pressure within thebuilding and controlling the temperature and therefore, the pressure,within the shaft 40, the so-called stack effect can be minimized oravoided.

In one example, a controller 60 is assigned to controlling the airpressure on each level within the building on an individual level basis.In another example, groups of building levels are controlled as a singlezone. Having each level individually controlled or groups of levelscontrolled in zones allows for managing different pressure levels atdifferent relative heights within the building to accommodate variationsthai occur along the length or height of the shaft 40 and the airpressure differences that occur outside of the building at elevationscorresponding to different building levels. Given this description,those skilled in the art will be able to select whether individual levelcontrol or zone control Will best meet the needs of their particularsituation.

Known relationships between outside air temperature and air pressure andknown air pressure control techniques can be employed to achieve airpressures at various levels within a building to achieve a desiredpressure differential between a useable or occupied space of a buildingand a vertically extending shaft. Those skilled in tire art will be ableto select from among such known techniques to meet the needs of theirparticular situation.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe essence of this invention. The scope of legal protection given tothis invention can only be determined by studying the following claims.

1. An elevator hoistway, comprising: a shaft through which an elevatorcab can move; and a temperature control mechanism associated with, theshaft to control a temperature within the shaft such that thetemperature in the shaft corresponds to an outdoor temperature near theshaft, the temperature control mechanism directing airflow within theshaft in a first direction when the outdoor temperature is lower than,the temperature in the shaft and directing airflow within the shaft in asecond, opposite direction when the outdoor temperature is higher thanthe temperature in the shaft.
 2. The elevator hoistway of claim 1,wherein the temperature control mechanism comprises at least one openingnear each of opposite ends of the shaft, each of the openings permittingairflow between the shaft and an outdoor environment near the shaft. 3.The elevator hoistway of claim 2, including at least, one temperaturesensor that provides an indication of the temperature in at least aportion of the shaft.
 4. The elevator hoistway of claim 3, including ansir mover that selectively varies an amount of airflow between the shaftand the outdoor environment responsive to an indication from thetemperature sensor that the temperature in the shaft does not correspondto the outdoor temperature within a selected range,
 5. The elevatorhoistway of claim 2, wherein the openings establish an airflow passagethrough the shaft for outdoor air to flow through the shaft
 6. Theelevator hoistway of claim 1, wherein the temperature control mechanismmaintains the temperature in the shaft approximately equal to theoutdoor temperature.
 7. A method of controlling airflow through agenerally vertical shaft in a building having a plurality levels,comprising the steps of: adjusting a temperature in the shaft tocorrespond to an outdoor temperature outside of the building; andcontrolling an air pressure of at least one level of the building basedupon the temperature in the shaft.
 8. The method of claim 7, includingadjusting the air pressure of the at least one level to maintain apressure difference between the shaft and the level within a selectedrange.
 9. The method of claim 7, including controlling the air pressureof each of the plurality of levels individually.
 10. The method of claim7, including grouping at least two of the plurality of levels in a zoneand controlling the air pressure of the zone,
 11. The method of claim 7,including controlling the air pressure of each of the plurality oflevels to achieve a desired pressure differential between the shaft andeach level.
 12. The method of claim 7, including increasing an amount ofairflow on at least one of the levels to increase the pressure on the atleast one level.
 13. The method of claim 7, wherein the shaft comprisesone of a stairwell, or an elevator hoistway,
 14. The method of claim 7,including directing airflow in the shaft in a first direction when theoutdoor temperature is lower than the temperature in the shaft and in asecond, opposite direction when the outdoor temperature is higher thanthe temperature in the shaft.
 15. The method of claim 7, wherein thebuilding includes a plurality of generally vertical shafts and themethod includes coordinating the temperatures within the shafts.
 16. Abuilding comprising: a plurality of levels; at least one elevatorhoistway shaft that provides access to at least some of the plurality oflevels; at least one stairwell shaft that provides access to at leastsome of the plurality of levels; and a temperature, control mechanismassociated with each of the shafts to control a temperature within eachshaft such that the temperatures in the shafts are coordinated andcorrespond to an outdoor temperature outside of the building,
 17. Thebuilding of claim 16, comprising a pressure control device that controlsan air pressure on each of the at least some of the plurality of levels.18. The building of claim 17, wherein the pressure control devicemaintains the air pressure on each level to achieve a desired pressuredifferential between the air pressure on the level and an air pressurein at least the elevator hoistway shaft
 19. The building of claim 16,wherein the temperature control mechanism directs airflow within atleast the elevator hoistway shaft in a first direction when the outdoortemperature is lower than the temperature in the elevator hoistway shaftand in a second opposite direction when the outdoor temperature ishigher than the temperature hi the elevator hoistway shaft.
 20. Thebuilding of claim 19, wherein the temperature control mechanism alsodirects airflow within the stairwell shaft in the first and seconddirections.